1、Designation: E 1640 04Standard Test Method forAssignment of the Glass Transition Temperature ByDynamic Mechanical Analysis1This standard is issued under the fixed designation E 1640; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the assignment of a glasstransition temperature (Tg) of materials using dynamic m
3、e-chanical analyzers.1.2 This test method is applicable to thermoplastic poly-mers, thermoset polymers, and partially crystalline materialswhich are thermally stable in the glass transition region.1.3 The applicable range of temperatures for this testmethod is dependent upon the instrumentation used
4、, but, inorder to encompass all materials, the minimum temperatureshould be about 150C.1.4 This test method is intended for materials having anelastic modulus in the range of 0.5 MPa to 100 GPa.1.5 Electronic instrumentation or automated data analysisand data reduction systems or treatments equivale
5、nt to this testmethod may also be used.NOTE 1The user bears the responsibility for determining the preci-sion, accuracy, and validity of the techniques and measurements madeusing dynamic mechanical analyzers in accordance with this standard.1.6 SI units are the standard.1.7 This standard is similar
6、to IEC 61006 except thatstandard uses the peak temprature of the mechanical loss peakas the glass transition temperature while this standard uses theextrapolated onset temperature of the loss modulus change.1.8 This standard does not purport to address all of thesafety concerns, if any, associated w
7、ith its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 4092 Terminology Relating to Dynamic MechanicalMeasurements in
8、PlasticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 1142 Terminology Relating to Thermophysical PropertiesE 1363 Test Method for Temperature Calibration of Ther-momechanical AnalyzersE 1545 Test Method for the Determination of Glass Transi-tion
9、Temperatures by Thermomechanical AnalysisE 1867 Test Method for Temperature Calibration of Dy-namic Mechanical AnalyzersE 2254 Test Method for Storage Modulus Calibration ofDynamic Mechanical Analyzers2.2 Other Standards:SRM 18R-94 Recommended Method for Glass TransitionTemperature (Tg) Determinatio
10、n by DMA of OrientedFiber-Resin Composites3IEC 61006 Methods of Test for the Determiantion of theGlass Transition Temperatue of Electrical Insulating Ma-terials43. Terminology3.1 Definition:3.1.1 Specific technical terms used in this document aredefined in Terminology D 4092 and E 1142.3.1.2 dynamic
11、 mechanical analyzerany of various com-mercial or experimental devices used to study the viscoelasticresponse of a specimen under a forced or free resonantoscillatory load. The force may be applied in torsion, flexure,or a combination of tension and compression.4. Summary of Test Method4.1 Aspecimen
12、 of known geometry is placed in mechanicaloscillation at either fixed or resonant frequency and changes inthe viscoelastic response of the material are monitored as afunction of temperature. Under ideal conditions, the glasstransition region is marked by a rapid decrease in the storagemodulus and a
13、rapid increase in the loss modulus. The glass1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on TestMethods and Recommended Practices.Current edition approved June 1, 2004. Published July 2004. Originally
14、 approvedin 1994. Last previous edition approved in 1999 as E 1640992For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM w
15、ebsite.3Available from Cuppliers of Advanced Composite Materials Association,Arlington, VA.4Available from American National Standards Institute (ANSI), New York, NY.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.transition of the t
16、est specimen is indicated by the extrapolatedonset of the decrease in storage modulus which marks thetransition from a glassy to a rubbery solid.5. Significance and Use5.1 This test method can be used to locate the glasstransition region and assign a glass transition temperature ofamorphous and semi
17、-crystalline materials.5.2 Dynamic mechanical analyzers monitor changes in theviscoelastic properties of a material as a function of tempera-ture and frequency, providing a means to quantify thesechanges. In ideal cases, the temperature of the onset of thedecrease in storage modulus marks the glass
18、transition.5.3 A glass transition temperature ( Tg) is useful in charac-terizing many important physical attributes of thermoplastic,thermosets (see SRM 18R-94), and semi-crystalline materialsincluding their thermal history, processing conditions, physicalstability, progress of chemical reactions, d
19、egree of cure, andboth mechanical and electrical behavior. Tgmay be determinedby a variety of techniques and may vary in accordance with thetechnique.5.4 This test method is useful for quality control, specifica-tion acceptance, and research.6. Interferences6.1 Because the specimen size will usually
20、 be small, it isessential that each specimen be homogeneous and/or represen-tative of the material as a whole.6.2 An increase or decrease in heating rates from thosespecified may alter results.6.3 A transition temperature is a function of the experimen-tal frequency, therefore the frequency of test
21、must always bespecified. (The transition temperature increases with increasingfrequency.) Extrapolation to a common frequency may beaccomplished using a predetermined frequency shift factor orassuming the frequency shift factor of about 8C per decade offrequency.57. Apparatus7.1 The function of the
22、apparatus is to hold a specimen ofuniform dimension so that the sample acts as the elastic anddissipative element in a mechanically oscillated system. Dy-namic mechanical analyzers typically operate in one of severalmodes. See Table 1.7.2 The apparatus shall consist of the following:7.2.1 Clamps, a
23、clamping arrangement that permits grippingof the specimen. Samples may be mounted by clamping at bothends (most systems), one end (for example, torsional pendu-lum), or neither end (free bending between knife edges).7.2.2 Oscillatory Stress (Strain), for applying an oscillatorydeformation (strain) o
24、r oscillatory stress to the specimen. Thedeformation may be applied and then released, as in freelyvibrating devices, or continuously applied, as in forced vibra-tion devices.7.2.3 Detector, for determining the dependent and indepen-dent experimental parameters, such as force (or stress), dis-placem
25、ent (or strain), frequency, and temperature. Tempera-tures should be measurable with an accuracy of 60.5 C, forceto 61 %, and frequency to 60.1 Hz.7.2.4 Temperature Controller and Oven, for controlling thespecimen temperature, either by heating, cooling (in steps orramps), or by maintaining a consta
26、nt experimental environ-ment. The temperature programmer shall be sufficiently stableto permit measurement of specimen temperature to 60.5C.The precision of the required temperature measurement is61.0 C.7.2.5 Output Device, capable of displaying the storagemodulus (either linearly or logarithmically
27、) on the Y axisincreasing in the upward direction and temperature on the Xaxis increasing to the right.NOTE 2Some instruments suitable for this test may display onlylinear or logarithm storage modulus while others may display either linearand/or logarithm storage modulus. Care must be taken to use t
28、he samemodulus scale when comparing unknown specimens, and in the compari-son of results from one instrument to another.7.3 Nitrogen, Helium or other gas supplied for purgingpurposes.7.4 Calipers or other length measuring device capable ofmeasuring dimensions (or length within)6 0.01 mm.8. Precautio
29、ns8.1 Toxic and corrosive, or both, effluents may be releasedwhen heating some materials and could be harmful to person-nel and to apparatus.8.2 Multiple TransitionsUnder some experimental condi-tions it is possible to have transitions secondary to the primaryglass transition. Secondary transitions
30、may be related to theglass transition of a second polymeric phase, melt processes,crystallization, chemical reactions, the motion of groups pen-dent to the main backbone or the crankshaft motion of thepolymer backbone.9. Samples9.1 Samples may be any uniform size or shape, but areordinarily analyzed
31、 in rectangular form. If some heat treatmentis applied to the specimen to obtain this preferred analyticalform, such treatment should be noted in the report.9.2 Due to the numerous types of dynamic mechanicalanalyzers, sample size is not fixed by this method. In manycases, specimens measuring betwee
32、n 1 3 5 3 20 mm and1 3 10 3 50 mm are suitable.NOTE 3It is important to select a specimen size appropriate for both5Ferry, D. “Viscoelastic Properties of Polymers,” John Wiley dec = decaying amplitude; forced = forced oscillation;CA = constant amplitude; res = resonant frequency; fix = fixed frequen
33、cy;CS = controlled stress.E1640042the material and the testing apparatus. For example, thick samples may berequired for low modulus materials while thin samples may be requiredfor high modulus materials.10. Calibration10.1 Calibrate the storage modulus and temperature signalsin accordance with Test
34、Methods E 1867 and E 2254, respec-tively.11. Procedure11.1 Mount the specimen in accordance with procedurerecommended by the manufacturer.11.2 Measure the length, width, and thickness of the speci-men to an accuracy of 60.01 mm.11.3 Maximum strain amplitude should be within the linearviscoelastic ra
35、nge of the material. Strains of less than 1 % arerecommended and should not exceed 5 %.11.4 Conduct tests at a heating rate of 1 C/min and afrequency of 1 Hz. Other heating rates and frequencies may beused but shall be reported.NOTE 4The glass transition temperature measured by dynamic me-chanical m
36、easurements is dependent upon heating rate and oscillatoryfrequency. The experimental heating rate and the frequency of oscillationshould be slow enough to allow the entire specimen to reach satisfactorythermal and mechanical equilibration. When the heating rate or oscillatoryrate is high, the exper
37、imental time scale is shortened, and the apparent Tgis raised. Changing the time scale by a factor of 10 will generally result ina shift of about 8 C for a typical amorphous material. The effect of thesevariables on the temperature of the tangent delta peak may be observed byrunning specimens at two
38、 or more rates and comparing the results (seeappendix).NOTE 5Where possible in automated systems, a minimum of one datapoint should be collected for each C increase in temperature. At low andhigh frequencies, use care in the selection of scanning rate and frequencyrate; select test conditions and a
39、data collection rate that will ensureadequate resolution of the mechanical response of the specimen. Forexample, select a heating rate that allows the specimen to complete at leastone oscillation for each C increase in temperature.11.5 Measure and record the storage modulus, from 30 Cbelow to 20 C a
40、bove the suspected glass transition region.12. Calculation12.1 For the purpose of this test method the glass transitionshall be taken as the extrapolated onset to the sigmoidal changein the storage modulus observed in going from the hard, brittleregion to the soft, rubbery region of the material und
41、er test.NOTE 6Storage modulus may be displayed on a linear or logarithmicscale. The reported glass transition temperature will differ depending uponthe scale chosen. The scale type (for example, linear or logarithmic) shallbe reported and must be the same for all parties comparing results.12.1.1 Con
42、struct a tangent to the storage modulus curvebelow the transition temperature.12.1.2 Construct a tangent to the storage modulus curve atthe inflection point approximately midway through the sigmoi-dal change associated with the transitions.12.1.3 The temperature at which these tangent lines inter-se
43、ct is reported as the glass transition temperature, Tg(see Fig.1).NOTE 7Under special circumstances agreeable to all parties, othertemperatures taken from the storage modulus, loss modulus, or tangentdelta curve may be taken to represent the temperature range over whichthe glass transition takes pla
44、ce. Among these alternative temperatures arethe peak of the loss modulus (Tl) or tangent delta (Tt) curves as illustratedin Fig. 2 and Fig. 3, respectively. These temperatures are generally in theorder Tg Tl Tt.12.2 For fixed frequency measurements at 1 Hz.12.2.1 Report the mean value of duplicate d
45、eterminations asTg.12.3 For measurements made at frequencies other than 1Hz.12.3.1 Using a predetermined frequency shift factor (k) (seeappendix), calculate the first approximation of the glass tran-sition temperature (Tl8) using equation 1.Tl8 5 T 1T2klogF1Hz(1)FIG. 1 Storage ModulusFIG. 2 Loss Mod
46、ulusE164004312.3.2 Calculate the glass transition temperature usingequation 2:T15 T 1TT18klogF1Hz(2)where:k = Predetermined Frequency Shift Factor (see Appen-dix X1.1)F = Frequency of Measurement (Hz)T = Glass Transition Temperature Observed at Fre-quency F (K)Tl8 = First Approximation for the Glass
47、 Transition Tem-perature at 1 Hz (K)Tl= Glass Transition Temperature at 1 Hz (K)Example:k = 12,417KF =2HzT = 100 C = 373KT8 =373K 1373K! 373K!212,417Klog 2 5 373K 2 3.37K= 369.62 KT =373 1373K! 369.62K!212,417Klog 2 5 373K 23.34K= 369.66 K = 96.5 C13. Report13.1 The report shall include the followin
48、g:13.1.1 A complete identification and description of thematerial testing including dimensions and any pretreatment.13.1.2 A description of the instrument used to perform thetest.13.1.3 A description of the temperature calibration proce-dure used.13.1.4 Whether linear or logarithmic storage modulus
49、wasdisplayed.13.1.5 The calculated glass transition temperature.13.1.6 The frequency of test and any extrapolation proce-dures used to provide results comparable at 1 Hz.13.1.7 The dynamic mechanical curves recorded.13.1.8 The specific dated edition of this method used.14. Precision and Bias14.1 An interlaboratory study of the measurement of theglass transition temperature of an epoxy composite was con-ducted in 1992. Following temperature calibration using apolystyrene thermoplastic polymer (a secondary referencematerial specifically prepared for this test
